John a



J. A. DAVIS. l TURN TABLE FOB TALKING MACHINES.

APPLICATION FILED JAN. 3l, 1920.

neissued Mar.23,1920. I 14,823.

Suma/whom Jbkm/Zavis,

` saw/w@ STATES PATENT OFFRE! JOHN A."DAVIS,I E THE UNITED STATES NAVY; U1

-` i rnnnf'rABLn son TAnKINMcnrNEsl I To alt 'whom it 'may concer/,-

Be itknown that I,

i the United States [Navy 'a citizen `of the f United States ofAmerica, andwhose postoffice address is yNavy Department, .Washi ington, D. ,`C., have invented new and useful Improvements in `'Iurnf'lables vfor Talking-Machines,v of lyvhichkthe following is a...

` "specification My invention 'has for its obj ect a new and i improved turn table Jfor talking machines"v and y particularly" forelectrically operated 'p machines although it may be usedy with equal success" on those which are x mechanically operated.

' At the present time vmany talking .mas "chines are operated electric motors theI l current for which istakenfro'm the ordifl 'c nary lighting circuit. This method of ops` erationihascertain obvious advantages butl serious difficulties havey arisen,` particularly as `the result ofthe use of metallic turntables on whichthe records are placed. The noise of the driving mechanism is transmitted throughthe spindle to the metallic "turn ltable lwhichiheilig"resonant tends to"magnify` lit and.'y distribute itfthus increasingthe ob` jectionablefnoisefThe'` vibrations of the 'c resonant'turnftable 'are to some extent transf" mitted to fthe record and^thusfthrough the needle "to the sound box `interfering with' the reproduction'of the 'frecord andy the purity of; theV tone therefromand' int'roduc-v y:'"ing extraneousy noises into the sound rey-jc .3.5

production.

y y Furthermore as electrically operated talky v`ingflnachines are arranged 'orconnection' c i with the ordinary lamp circuit which is comf inonly'l'IQ 01'1220' volts andas there is al-` ways dangerl -cfa short circuit; in the instrument, there i's'danger ofjan felectric'shock` toy any one touching al metallic turntable which is in electrical connection through the spindle with the other metallic parts of the" instrument.' There is also equaldanger o fire -from a shortscircuit.

Accordingly my invention has for its object anew and improved turn table which overcomes completely the various objections previously mentione The turn table embodyin my invention is molded from a suitable insu ating compound such for instance as one in which pulverized asbestos, mica, gum shellac and asphaltum are ingredients, This material is plastic 'i view` of a Specification offlteissued `Letters Patent. ReiSSuedMar, 23,1920, j ongm`1 1jto.i,ass,o19, datauaeh as, 1919,:ser'ia1 No.y 113,564, med Aug'st 7; 1e1e. ,rpncatan `for reissue i, led January. 31, 1920.1.'Seria1 2110.355364.` n

l when heated and is capablev of being molded l fromvthe following description` when taken y 1n connection with'the accompanying drawings andthe novelfeatur'es thereof will be pointed out and clearly' defined in the'claims at the closeof thiss eciiication. l

` In the drawings, igure Al is atopfplan turn".l tabler embodyingA my invention'. y y' y y Fig.l 2 is aside elevation of the same. yFig. 3is a'section on line 34-3 of Fig. 1. Referring 'tol the drawings there is shown at Al the disk portion of the turn table and at B the hub. Th'eunderside of the disk v'is stiflened by ribs yC whichv connect.y with theJ hub and increasev the rigidity of the inlshed structure' so that it can not be 'sprung gif dropped-or .leaned upon *whenv in'place upon' the :spindleof the machine with which it is used." These parts are -moldedintegral' `froml theinsulating material chosen as 'Ior instance the plastic composition r`mentioned above. The upper: side of the turntable is covered with feltD on which the record rests.` This felt serves tol make a' frictional contact between the turn table and the record. In my preferred form, I provide an annular piece or ring of felt which extends `from apoint a short ydistance inside ofthe `circumference of the turn table'to a point from vone ltothree inches kfrom. the center of the diskA. I'also `form' anannular depresfsionE' vin th'ejsurface of theturn tableunyder'neath the vouter "edgeofthe disk lof felt and another 'annular de ression F underneath the inner ede o the felt thereby causing the edges o felt to lie slightly be shoulderv has a gradual slope. The edges,

v having in the upper surface two annular detherefore, of the felt disk D are entirely below the eneral surface of the table, the edges of th and the outer pfriphery abutting up against the shoulders Thus the upper surface ofthe felt has a sort of crowned effect and the felt is enabled to support the record free from any contact whatever with the composition body 0f the table, although there are no upwardly projecting shoulders or nubs. This construction enables the felt to be applied to the turn table more smoothly and rapidly and it is less likely to become unsecured around its edges and to vwork up as has heretofore been the case. It also makes it easier to put the record in place or to remove it, as the edge of the record is not in contact with the turn table.

Since the turn table is made of insulating material, the current by which the electr1c motor is operated cannot be transmitted through the turn table to the operator or to any article which may be in contact with the turn table'thus eliminating the danger of fire and 'increasing the safety of the user of the machine. Since the insulating material of which the turn table is constructed is nonresonant, sounds generated in the in-v strument are not transmitted through the spindle and increased and distributed by the turn table. The sound reproduction is not interfered with by vibration of the turn table transmitted to the record and thence through the needle to the sound box.

Furthermore, in case the instrument below the turn table becomes charged with static electricity, as ma be the case particularly in cold weather, t e charge can not be communicated to the sound box to the injury of the tone-reproduction.

What yI claim is 1. A turn table for talking machines, the body portion of which'consists of 'a disk pressions which are concentric with each -other and with the periphery of the disk,

one ofwsaid depressions being located'at some ldistance inside of the margin of the disk, the other of said depressions being located at a considerable dista-nce nearer the center of the disk, the outer depression having an abrupt shoulder at its outer periphery, the bottom of the depression having a gradual slope from its inner to its outer e felt both :on the inner peripheryand G respectively, leaving no exposed portion whatever of the edge.

edge, the "inner depression having'an abrupt shoulder at its inner edge, the bottom of said depressionhavinga gradual slope from its outer periphery `to its inner periphery, and an annular piece of felt secured to the surface of the table disk covering the space between the shoulders of said twodepressions, the innerl and outer edges of said felt lying within said depressions vso that the edges of the felt do not roject above the shoulders formed by the epressions in the table disk..

2. A turn table for talking machines, the body portion of which'consists fof a disk 'having in its upper surface an annular depression which is concentric with the periphery of the disk and which is located toward the inner part of the disk, thevbottomof said depression having av gradual slope, and a circular strip of felt secured to the surfacer of the diskand having its edge lying within said depression so as not to project above said disk surface,the main portion of the .felt beingy disposed above the plane of said surface.

3. A turn table for talking` machines, the body portion of which consists of a disk having in the upper surface an annular depression which is concentric with the eripheraledge of the disk and which is ocated at a slight distance inside ofsaid peripheral edge, said depression having an abrupt shoulder at its outer periphery, the bottom of the depression having a gradual slope from itsfinner to its outer edge, and a circular strip of felt secured to the surface of the disk and having its outer edge lying within said depression so that its said edge does not project above the shoulder formed by thev depression.

4'. A turn table for talking machines, the body portion of which consists of a disk having in its uppersurface an annular depressen which is concentric with the periphery of the disk, said depression .having an abrupt shoulder at one of its peripheral edges, the bottom o f said depression having a gradual yslope away froml said shoulder, and a circular strip of ,felt secured to the surface of the disk and having an edge thereof lying within said depression, so that soi 

